Alkyl polyglycosides have been known for many years, having been first synthesized in the early 1900 by Emile Fischer. Despite this, the products were of little commercial interest until much later.
U.S. Pat. No. 4,393,203 issued Jul. 12, 1983 to Mao et al, incorporated herein by reference, disclose that long chain fatty alcohols can be removed from alkyl polysaccharide products in thin film evaporators to achieve fatty alcohol levels of less than about 2% without excessive discoloration of the alkyl polysaccharide. This allowed for a more cosmetically acceptable product to be developed that is more surface active. The presence of the free fatty alcohol in the mixture, allows for a more water-soluble product, by removing the water insoluble alcohol.
One of the most significant patents is U.S. Pat. No. 5,003,057 issued Mar. 26, 1991 to McCurry et al incorporated herein by reference, provides for a process for preparing glycosides from a source of saccharide moiety and an alcohol in the presence of a hydrophobic acid catalyst is provided. An example of such a catalyst is dinonylnaphthalenemonosulfonic acid. The use of such catalysts provides a number of process advantages, which includes the reduced production of polar by-products. Preferred glycosides produced by the process are higher alkyl glycosides useful as surfactants.
U.S. Pat. No. 3,598,865 (Lew) discloses the production of higher alkyl (C−8-C25) glycosides from a monosaccharide or source thereof and a higher monohydric alcohol in the presence of a latent solvent (lower alcohols) and an acid catalyst selected from the group consisting of sulfuric acid, hydrochloric acid, phosphoric acid, phosphorous acid, toluenesulfonic acid, and boron trifluoride.
U.S. Pat. No. 3,219,656 (Boettner) discloses a process for producing a higher alkyl glycoside by reacting glucose with methanol in the presence of a macroreticular-structured sulfonic acid resin, anhydrous and in the acid form, to produce methyl glycoside which is reacted without isolation with butanol to form butyl glycoside and which in turn is reacted with a higher alcohol to form a surface active higher alkyl glycoside.
U.S. Pat. No. 3,839,319 (Mansfield) discloses a process for producing alkyl glycosides by direct, acid catalyzed reaction of a higher alcohol and a saccharide. The acid catalysts are mineral acids such as hydrochloric and sulfuric, and sulfonic acid exchange resins
The compounds known before the current invention have been primarily used in industrial applications like detergents for dish wash. This is due in part to inherent drying that occurs when these materials are applied to the skin. Many people, one of which is Cognis, have introduced blends of alkyl polyglycosides and traditional surfactants to overcome these limitations. The blending of other alternative surfactants, while demonstrating a long felt need for improvement in the performance of the product, does not address underlying difficulties in the molecule.
U.S. Pat. No. 4,297,290 to Stockberger issued Oct. 27, 1981 teaches that sorbitan fatty acid esters can be prepared by forming anhydro sorbitol (a mixture of sorbitans, isosorbide, and unreacted sorbitol) by acid-catalyzed anhydrization, then reacting the resulting anhydro sorbitol with a fatty acid in the presence of a base at a temperature not exceeding about 215° C. Use of temperatures not over 215° C. results in products having substantially less color than those obtained at higher temperatures. It is these hydrophobic materials that are the raw material for synthesis of the emulsifiers of the present invention.
U.S. Pat. No. 7,556,653 to LaVay et al issued Jul. 7, 2009 entitled Polymeric silicone alkoxyglyceryl softeners teaches a class of polyesters that are lightly crosslinked polyesters made by reacting alkoxy glyceryl units (linked by the reaction of their hydroxyl groups) to the carboxyl group of dimer acid. As will become clear, lightly crosslinked as used herein relates to reactions in which there is an excess of hydroxyl groups on a molar basis to carboxylic groups on the dimer acid. The polymers and a contribute softness, lubricity and antistatic properties when applied to hair, skin, textile fiber and paper. This patent teaches that dimer acid can be used to crosslink polysorbates to make conditioners. This patent provides conditioners not emulsifiers, and lacks the critical element of alkyl polyglycoside and crosslinker.
U.S. Pat. No. 7,507,399 issued Mar. 24, 2009 to O'Lenick entitled Functionalized polymeric surfactants based upon alkyl polyglycosides teaches a series of multifunctional polyglycosides derivatives that are made by the polymerized by the reaction of 1,3 dichloro isopropanl and polyglycosides, together with a functionalizing agent that contains a sulfate, sulfonate, quaternary nitrogen, or a phosphate group. This patent lacks the critical element of the sorbitan ester to make an emulsifier.
All patents referenced above are incorporated herein by reference. None of the patents referenced above either alone or combination teach or suggest the making of the compounds of the present invention, namely combining the sorbitan ester with the alkylpolyglycoside and the crosslinker.